If you are ever at a NASCAR event, then I recommend the Sprint FanView. From your RV or seat, you can only see what's immediately in front of you.

The FanView gives you the same video that you would get at home from the comfort of your couch. It's also got several in-car views and audio from all the drivers/pitcrews. If you are in your RV, then bring along some speakers and you can blast it for your entire family/group to hear. I rented two headsets, but we rarely used more than just the one. We were located directly next to PA system speakers, so we didn't actually need volume, as the PA was blasting the same audio as the FanView.

Last year at Pocono, we rented the audio only version. I don't recommend those. The FanView is a bit more expensive ($50 for the weekend) and completely worth it. You don't have to return the FanView immediately after the race. You can return it the next day at any UPS Store. This frees you up to party after the race.